Apparatus and method for transmitting and receiving in a multi-antenna system

Abstract

Apparatuses and methods for transmitting and receiving in a multi-antenna system are provided. A receiver for reducing a quantization error of channel information feedback in a multi-antenna system includes a restore vector generator for selecting a codeword c k and d determining a real part w k real and an imaginary part w k imag of a restore vector corresponding to the codeword; and a post-processor for performing post-processing by multiplying the real part w k real of the restore vector by a first reception signal and multiplying the imaginary part w k imag of the restore vector by a second reception signal.

What is claimed is: 
     
       1. A receiver for reducing a quantization error of channel information feedback in a multi-antenna system, comprising:
 a channel estimator for estimating a channel between a transmitter and the receiver, and forming a channel matrix; 
 a restore vector generator for selecting a codeword c k  for precoding and determining a real part w k   real  and an imaginary part w k   imag  of a restore vector based on the channel matrix and the selected codeword c k ; and 
 a post-processor for receiving a first reception signal and a second reception signal, performing post-processing by multiplying the real part w k   real  of the restore vector by the first reception signal and multiplying the imaginary part w k   imag  of the restore vector by the second reception signal. 
 
     
     
       2. The receiver of  claim 1 , wherein the second reception signal comprises a complex conjugate signal of the first reception signal. 
     
     
       3. The receiver of  claim 1 , wherein the first reception signal is received in a first time slot and the second reception signal is received in a second time slot. 
     
     
       4. The receiver of  claim 1 , wherein the selected codeword c k  minimizes a norm of the restore vector with respect to the selected codeword c k . 
     
     
       5. A transmitter for reducing a quantization error of channel information feedback in a multi-antenna system, comprising:
 a precoder for pre-coding a transmission signal using a precoding matrix; and 
 a Radio Frequency (RF) processor for transmitting the precoded transmission signal via at least one antenna in a first time slot and transmitting a complex conjugate signal of the precoded transmission signal via at least one antenna in a second time slot, 
 wherein the precoded transmission signal and the complex conjugate signal are transmitted via a same antenna, 
 wherein the precoding matrix comprises codewords indicating codeword indices fed back from a plurality of terminals, and 
 wherein each of the codewords minimizes a norm of a restore vector with respect to a respective codeword. 
 
     
     
       6. The transmitter of  claim 5 , wherein the restore vector includes a real part w k   real  and an imaginary part w k   imag , which is based on a channel matrix and a selected codeword c k , and
 wherein the channel matrix is formed by an estimated channel. 
 
     
     
       7. A method for reducing a quantization error of channel information feedback in a multi-antenna system, comprising:
 estimating a channel between a transmitter and a receiver, and forming a channel matrix; 
 selecting, by a restore vector generator, a codeword c k  for precoding; 
 determining, by the restore vector generator, a real part w k   real  and an imaginary part w k   imag  of a restore vector based on the channel matrix and the selected codeword; 
 receiving a first reception signal and a second reception signal; and 
 performing, by a post-processor, post-processing by multiplying the real part w k   real  of the restore vector by the first reception signal, and multiplying the imaginary part w k   imag  of the restore vector by the second reception signal. 
 
     
     
       8. The method of  claim 7 , wherein the second reception signal includes a complex conjugate signal of the first reception signal. 
     
     
       9. The method of  claim 7 , wherein the first reception signal is received in a first time slot and the second reception signal is received in a second time slot. 
     
     
       10. The method of  claim 7 , wherein the selected codeword minimizes a norm of the restore vector with respect to the selected codeword. 
     
     
       11. A method for reducing a quantization error of channel information feedback in a multi-antenna system, comprising:
 pre-coding, by a precoder, a transmission signal using a precoding matrix; and 
 transmitting, by a Radio Frequency (RF) processor, the precoded transmission signal via at least one antenna in a first time slot; and 
 transmitting, by the RF processor, a complex conjugate signal of the precoded transmission signal via at least one antenna in a second time slot, 
 wherein the precoded transmission signal and the complex conjugate signal are transmitted via a same antenna, 
 wherein the precoding matrix includes codewords indicating codeword indices fed back from a plurality of terminals, and wherein each of the codewords minimizes a norm of the restore vector with respect to a respective codeword. 
 
     
     
       12. The method of  claim 11 , wherein the restore vector includes a real part w k   real  and an imaginary part w k   imag , which is based on a channel matrix and a selected codeword c k , and
 wherein the channel matrix is formed by an estimated channel. 
 
     
     
       13. A receiver for reducing a quantization error of channel information feedback in a multi-antenna system, comprising:
 a Radio Frequency (RF) processor for receiving a transmission signal in a first time slot and receiving a complex conjugate signal of the transmission signal in a second time slot; 
 a channel estimator for estimating a channel between a transmitter and the receiver, and forming a channel matrix; 
 a restore vector generator for selecting a codeword c k  to postcode the transmission signal and determining a real part w k   real  and an imaginary part w k   imag  of a restore vector to based on the channel matrix and the selected codeword c k ; and 
 a post-processor for performing a post-processing by multiplying the real part w k   real  of the restore vector by the transmission signal and multiplying the imaginary part w k   imag  of the restore vector by the complex conjugate signal of the transmission signal. 
 
     
     
       14. The receiver of  claim 13 , wherein the selected codeword c k  minimizes a norm of the restore vector with respect to the codeword c k . 
     
     
       15. A method for reducing a quantization error of channel information feedback in a multi-antenna system, comprising:
 receiving, by a Radio Frequency (RF) processor, a transmission signal in a first time slot; 
 receiving, by the RF processor, a complex conjugate signal of the transmission signal in a second time slot; 
 estimating a channel between a transmitter and a receiver, and forming a channel matrix; 
 selecting, by a restore vector generator, a codeword c k  to postcode the transmission signal; 
 determining, by the restore vector generator, a real part w k   real  and an imaginary part w k   imag  of a restore vector based on the channel matrix and the codeword c k ; and 
 performing, by a post-processor, post-processing by multiplying the real part w k   real  of the restore vector by the transmission signal and multiplying the imaginary part w k   imag  of the restore vector by the complex conjugate signal of the transmission signal. 
 
     
     
       16. The method of  claim 15 , wherein the codeword c k  minimizes a norm of the restore vector with respect to the codeword c k .